Printing machine cylinders which are driven, and particularly large cylinders which have high inertia and roll off against each other are potentially hazardous. The cylinders are designed to draw a web, for example of paper, between themselves. This tendency to pull anything between the cylinders presents a potential operator hazard.
It has previously been proposed to protect operators, as well as the printing machine roller surfaces, by placing a guard rail in advance of the nip formed between the cylinders and through which, normally, a paper web is to be drawn. Such safety rails, also referred to as finger safety rails, require holding apparatus which, if the cylinders are located on movable bearings or trunnions, that the safety rails move with the cylinder, that is, the safety rail must always be in front of the nip, even though the position of the nip may change upon readjustment of the cylinder shafts or bearings or trunnions. German Patent No. 1,918,173 describes such an arrangement.
While the arrangement so described works well, it has been found that, in operation, dirt, sprayed ink or damping fluid or the like may deposit on the holders for the safety rail. Access to the cylinders, for example to exchange a rubber blanket on a cylinder or a plate or the like then could be impaired.